The present invention relates to animal feed block compositions (hereinafter referred to as feed blocks) containing a growth promoter, such as avoparcin, and an organic or mineral acid and methods for enhancing the potency retention of the growth promoter in the feed blocks.
The incorporation of avoparcin-like complexes in animal feed blocks for enhancing the growth rate of animals is disclosed in U.S. Pat. No. 3,856,937, issued Dec. 24, 1974. However, when this growth promoter is incorporated into certain commercially-available feed blocks, avoparcin's potency is reduced at a rate of about 20% to 25% per week. The present invention provides methods whereby this reduction in potency is diminished, thereby providing feed blocks with improved growth promoter potency retention.